In MySQL when the mapping for space is changed to something other than
0x20 by defining a different collation, then space is not ignored when
comparing two strings.
This was happening because the function that performs the comparison
of two strings while ignoring ending spaces, was comparing the collation
value of a space with the ascii value of the ' ' character. This should
be changed to do comparison between the collated values.
low myisam_sort_buffer_size
Repair by sort (default) or parallel repair of a MyISAM table
(doesn't matter partitioned or not) as well as bulk inserts
and enable indexes some times didn't failover to repair with
key cache.
The problem was that after unsuccessful attempt, data file was
closed. Whereas repair with key cache requires open data file.
Fixed by reopening data file.
Also fixed a valgrind warning, which may appear during repair
by sort or parallel repair with certain myisam_sort_buffer_size
number of rows and length of an index entry (very dependent).
covering index
When two range predicates were combined under an OR
predicate, the algorithm tried to merge overlapping ranges
into one. But the case when a range overlapped several other
ranges was not handled. This lead to
1) ranges overlapping, which gave repeated results and
2) a range that overlapped several other ranges was cut off.
Fixed by
1) Making sure that a range got an upper bound equal to the
next range with a greater minimum.
2) Removing a continue statement
backport for bug#44059 from mysql-pe to mysql-5.1-bugteam
Using the partition with most rows instead of first partition
to estimate the cardinality of indexes.
is reached
Problem was bad error handling, leaving some new temporary
partitions locked and initialized and some not yet initialized
and locked, leading to a crash when trying to unlock the not
yet initialized and locked partitions
Solution was to unlock the already locked partitions, and not
include any of the new temporary partitions in later unlocks
- Read plug.in to fid the name of the engine to link with, does not have
to be same as engine dir
- Use engine dir when figuring out which libraries to build limbysqld with
- Make it possible for the CmakeLists.txt files in an engine to use
${engine}_LIBS to set additional libraries to link with
Example: NDBCLUSTER_LIBS = ndbclient
can lead to bad memory access
Problem: Field_bit is the only field which returns INT_RESULT
and doesn't have unsigned flag. As it's not a descendant of the
Field_num, so using ((Field_num *) field_bit)->unsigned_flag may lead
to unpredictable results.
Fix: check the field type before casting.
buffering is used
FORCE INDEX FOR ORDER BY now prevents the optimizer from
using join buffering. As a result the optimizer can use
indexed access on the first table and doesn't need to
sort the complete resultset at the end of the statement.
The pthread_cond_wait implementations for windows might
dead lock in some rare circumstances.
1) One thread (I) enter a timed wait and at a point in
time ends up after mutex unlock and before
WaitForMultipleObjects(...)
2) Another thread (II) enters pthread_cond_broadcast.
Grabs the mutex and discovers one waiter. It set
the broadcast event and closes the broadcast gate
then unlocks the mutex.
3) A third thread (III) issues a pthread_cond_signal.
It grabs the mutex, discovers one waiter, sets the
signal event then unlock the mutex.
4) The first threads (I) enters WaitForMultipleObjects
and finds out that the signal object is in a
signalled state and exits the wait.
5) Thread (I) grabs the mutex and checks result status.
The number of waiters is decreased and becomes equal
to 0. The event returned was a signal event so the
broadcast gate isn't opened. The mutex is released.
6) Thread (II) issues a new broadcast. The mutex is
acquired but the number of waiters are 0 hence
the broadcast gate remains closed.
7) Thread (I) enters the wait again but is blocked by
the broadcast gate.
This fix resolves the above issue by always resetting
broadcast gate when there are no more waiters in th queue.
Let
- T be a transactional table and N non-transactional table.
- B be begin, C commit and R rollback.
- N be a statement that accesses and changes only N-tables.
- T be a statement that accesses and changes only T-tables.
In RBR, changes to N-tables that happen early in a transaction are not immediately flushed
upon committing a statement. This behavior may, however, break consistency in the presence
of concurrency since changes done to N-tables become immediately visible to other
connections. To fix this problem, we do the following:
. B N N T C would log - B N C B N C B T C.
. B N N T R would log - B N C B N C B T R.
Note that we are not preserving history from the master as we are introducing a commit that
never happened. However, this seems to be more acceptable than the possibility of breaking
consistency in the presence of concurrency.
Let
- T be a transactional table and N non-transactional table.
- B be begin, C commit and R rollback.
- M be a mixed statement, i.e. a statement that updates both T and N.
- M* be a mixed statement that fails while updating either T or N.
This patch restore the behavior presented in 5.1.37 for rows either produced in
the RBR or MIXED modes, when a M* statement that happened early in a transaction
had their changes written to the binary log outside the boundaries of the
transaction and wrapped in a BEGIN/ROLLBACK. This was done to keep the slave
consistent with with the master as the rollback would keep the changes on N and
undo them on T. In particular, we do what follows:
. B M* T C would log - B M* R B T C.
Note that, we are not preserving history from the master as we are introducing a
rollback that never happened. However, this seems to be more acceptable than
making the slave diverge. We do not fix the following case:
. B T M* C would log B T M* C.
The slave will diverge as the changes on T tables that originated from the M
statement are rolled back on the master but not on the slave. Unfortunately, we
cannot simply rollback the transaction as this would undo any uncommitted
changes on T tables.
SBR is not considered in this patch because a failing statement is written to
the binary along with the error code and a slave executes and then rolls back
the statement when it has an associated error code, thus undoing the effects
on T. In RBR and MBR, a full-fledged fix will be pushed after the WL 2687.
1. BUG#46256 - drop table with unknown collation crashes innodb
Note: No testcase attached and has to be verified manually
Detailed revision comments:
r5799 | calvin | 2009-09-09 20:47:31 +0300 (Wed, 09 Sep 2009) | 10 lines
branches/5.1: fix bug#46256
Allow tables to be dropped even if the collation is not found,
but issue a warning.
Could not find an easy way to add mysql-test since it requires
changes to charsets and restarting the server. Tests were
executed manually.
Approved by: Heikki (on IM)
r5805 | vasil | 2009-09-10 08:41:48 +0300 (Thu, 10 Sep 2009) | 7 lines
branches/5.1:
Fix a compilation warning caused by c5799:
handler/ha_innodb.cc: In function 'void innobase_get_cset_width(ulint, ulint*, ulint*)':
handler/ha_innodb.cc:830: warning: format '%d' expects type 'int', but argument 2 has type 'ulint'
1. BUG#46000 - using index called GEN_CLUST_INDEX crashes server
Detailed revision comments:
r5895 | jyang | 2009-09-15 03:39:21 +0300 (Tue, 15 Sep 2009) | 5 lines
branches/5.1: Disallow creating index with the name of
"GEN_CLUST_INDEX" which is reserved for the default system
primary index. (Bug #46000) rb://149 approved by Marko Makela.
SELECT ... WHERE ... IN (NULL, ...) does full table scan,
even if the same query without the NULL uses efficient range scan.
The bugfix for the bug 18360 introduced an optimization:
if
1) all right-hand arguments of the IN function are constants
2) result types of all right argument items are compatible
enough to use the same single comparison function to
compare all of them to the left argument,
then
we can convert the right-hand list of constant items to an array
of equally-typed constant values for the further
QUICK index access etc. (see Item_func_in::fix_length_and_dec()).
The Item_null constant item objects have STRING_RESULT
result types, so, as far as Item_func_in::fix_length_and_dec()
is aware of NULLs in the right list, this improvement efficiently
optimizes IN function calls with a mixed right list of NULLs and
string constants. However, the optimization doesn't affect mixed
lists of NULLs and integers, floats etc., because there is no
unique common comparator.
New optimization has been added to ignore the result type
of NULL constants in the static analysis of mixed right-hand lists.
This is safe, because at the execution phase we care about
presence of NULLs anyway.
1. The collect_cmp_types() function has been modified to optionally
ignore NULL constants in the item list.
2. NULL-skipping code of the Item_func_in::fix_length_and_dec()
function has been modified to work not only with in_string
vectors but with in_vectors of other types.
